Method of installing plates on blade of plow or grader

ABSTRACT

A cart is configured to handle replaceable plates used on the blade of a plow or grader. The cart includes a wheeled frame and a plate holder configured to support the plate lengthwise in a generally upright orientation. The plate holder is supported on the frame by a parallelogram linkage that permits adjustment of the plate holder, and thereby the plate carried by the holder, without varying the orientation of these components. An inventive plate installation method is also disclosed. The method involves placing at least one plate on the height-adjustable plate holder carried on the mobile frame. The attachment holes defined in the plate are then aligned with the attachment holes defined in the blade.

RELATED APPLICATIONS

This is a Divisional application of application Ser. No. 09/248,586filed Feb. 11, 1999 now U.S. Pat. No. 6,241,227 issued Jun. 5, 2001.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

MICROFICHE APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to accessories used with plows(e.g., snow plows) and graders. More particularly, the present inventionconcerns a device for handling replaceable plates, such as cutting edgesand wear plates, used on the blades of plows and graders. The presentinvention also concerns the improved method of installing thereplaceable plates.

2. Discussion of Prior Art

The blade of a plow or grader is typically provided with at least onereplaceable plate for improving the cutting and/or plowing action of theblade and for increasing the life span of the blade. It is common toutilize a dual plate arrangement, which often includes a cutting edgesecured against the lower margin of the front face of the blade and awear plate secured over the cutting edge. The cutting edge projectsdownwardly below the lower margin of the blade and is customarily formedof a hard material, such as tungsten carbide. The wear plate is designedto cooperate with the cutting edge in improving blade operation anddurability. Particularly, the wear plate and cutting edge are preferablycoextensive, with the wear plate being superimposed over the cuttingedge. The wear plate is preferably formed of a stronger, more durablematerial (e.g., standard carbon steel) than the cutting edge. That is tosay, the cutting edge is typically formed of a brittle albeit hardmaterial, and the wear plate is consequently designed to absorb theimpact loads created as the blade encounters objects, such as rocks orother debris located on a roadway.

It will be appreciated that replacement plates extend across the entireblade and are consequently relatively long, even when divided intoseveral sections arranged end-to-end across the front of the blade. Forexample, a typical plow blade and the replacement plates used thereonwill be approximately twelve feet long (measured from side to side). Theplates are consequently unwieldy and heavy. Moreover, replacement of theplates traditionally involves two workers manually holding the plate offof the ground and moving the plate until the attachment holes in theplate align with the corresponding attachment holes defined in theblade, while a third worker inserts bolts through the aligned attachmentholes. It will also be appreciated that conventional replacement plateswill often weigh in excess of one hundred pounds. Thus, the conventionalsystem for replacing the plates used on the blade of a grader or plow islaborious, difficult and expensive.

OBJECTS AND SUMMARY OF THE INVENTION

Responsive to these and other problems, an important object of thepresent invention is to provide a system for simplifying andfacilitating the replacement of the plates used on the blade of a plowor grader. It is also important object of the present invention toprovide a device for assisting the worker with manipulation of theplates during installation and removal. Another important object of thepresent invention is to make the device inexpensive and simple inconstruction, yet sufficiently durable to withstand the rigorousoperating conditions encountered during blade replacement. Yet anotherobject of the present invention is to provide a system that permits theplates to be replaced by only one worker, without requiring the workerto manually hold the plates off of the ground during replacement.

In accordance with these and other objects evident from the followingdescription of the preferred embodiment, the present invention concernsa device in the form of a cart for handling the replaceable plates usedon the blade of a plow or grader. The cart includes a wheeled frame anda plate holder supported on the frame for up and down movement relativeto the ground. The plate holder is designed to support the plate in anorientation generally corresponding to the front face of the blade. Thistypically involves supporting the plate in an upright orientation sothat the plate may be placed against the generally upright front face ofthe blade. In some cases, the plate may be oriented at a slight anglerelative to vertical to correspond with the orientation and/or thecurvature of the front face of the blade.

The cart preferably includes a parallelogram linkage for supporting theplate holder on the frame, with the linkage maintaining the plateholder, and thereby the plate or plates supported thereon, in a singleorientation as the holder is raised and lowered. An actuator may beconnected between the frame and linkage for effecting raising andlowering of the plate holder. This is particularly useful when the cartis being used to install large, heavy plates. The cart may also beprovided with a tongue that facilitates movement of the cart into thedesired locations, especially in low clearance situations. The frame ofthe cart is preferably supported on caster wheel assemblies, and thetongue may be attached to the frame in several different locations toimprove maneuverability of the cart.

The present invention also concerns the improved method of installingthe replaceable plates. This method permits just one worker to installthe plates, without having to manually hoist the plates duringinstallation. Particularly, the installation method involves the stepsof supporting at least one plate on a mobile cart and aligning theattachment holes defined in the at least one plate with thecorresponding attachment holes defined in the blade. The plate ispreferably supported on a height-adjustable holder carried on the frameso that the height of the plate may be adjusted during the step ofaligning the attachment holes. Of course, alignment of the attachmentholes may also involve moving the cart into proximity with the blade.

Other aspects and advantages of the present invention will be apparentfrom the following detailed description of the preferred embodiments andthe accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Preferred embodiments of the invention are described in detail belowwith reference to the attached drawing figures, wherein:

FIG. 1 is a perspective view of a cart constructed in accordance withthe principles of the present invention, with the illustrated cartsupporting a replaceable plate as it is being installed on the blade ofa plow or grader;

FIG. 2 is an enlarged top plan view of the cart shown in FIG. 1;

FIG. 3 is an enlarged side elevational view of the cart shown in FIG. 1with parts being partly broken away to show the constructional detailsof the actuator, and particularly illustrating the cart being used toinstall the second replaceable plate (typically referred to as the wearplate) on the front blade of a plow or grader.

FIG. 4 is an enlarged side elevational view of the cart shown in FIG. 1,particularly illustrating the cart being used to install a replaceableplate on a relatively low blade, such as an underbody plow or grader;

FIG. 5 is a fragmentary perspective view of an alternative embodiment ofthe present invention, wherein an extension boom having a pair ofclamping mechanisms is provided for securely supporting a long plateand/or a plurality of plate sections; and

FIG. 6 is a enlarged vertical cross-sectional view of the alternativeembodiment, particularly illustrating a pair of replaceable platessupported on the extension boom as they are being installed on the bladeof a plow or grader.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning first to FIG. 1, the plate handling device 10 selected forillustration comprises a mobile cart designed to assist the operator ininstalling and removing the replaceable plates used on the blade of aplow or grader. As will subsequently be described, the illustrated cart10 permits a single user to install a plate, without having to hold theplate off the ground during installation. That is to say, theillustrated cart 10 permits the user to relatively effortlesslymanipulate a plate into the proper orientation with respect to theblade. It is particularly noted that the cart 10 generally includes awheeled frame 12, a tongue 14 projecting from the frame 12, a pair ofplate holders 16 and 18, a parallelogram linkage 20 supporting the plateholders 16 and 18 on the frame for relative up and down movement anactuator 22 coupled between the frame 12 and linkage 20 for controllingthe height of the holders 16 and 18, and various other parts associatedwith these primary components.

The wheeled frame 12 has a relatively low profile (e.g., see FIG. 4) andpreferably includes a pair of fore-and-aft extending U-shaped beams 24and 26 and a pair of flat, transverse cross-plates 28 and 30 (e.g., seeFIGS. 1 and 2) interconnecting the beams 24 and 26. It is noted thateach of the plates 28 and 30 is fixed to the top of the beams 24 and 26at a corresponding end thereof. In addition, each of the plates 28 and30 has sufficient length to project laterally outward of the beams 24and 26 to present overhanging portions. The illustrated frame 12 furtherincludes four caster wheel assemblies 32,34,36,38 connected to theoverhanging portions of the plates 28 and 30. Only the caster wheelassembly 34 will be detailedly described herein, with the understandingthat the remaining wheel assemblies are similarly constructed. Theassembly 34 includes a wheel 40 rotatably supported between the arms ofa yoke 42. The assembly 34 further includes a threaded fastener 44 forattaching the assembly to the corresponding overhanging portion of thecross-plate 28, with a traditional swivel (not shown) being providedbetween the yoke 42 and fastener 44 for allowing the yoke 42 to rotateabout an upright axis generally defined by the fastener 44. Thoseordinarily skilled in the art will appreciate that the caster wheelassemblies 32-38 permit the cart 10 to be moved in virtually anydirection across the support surface. In addition, it is not necessarythat the cart 10 be equipped with four caster wheels assemblies toprovide the desired multidirectional movement (e.g., two caster wheelassemblies and two fixed wheel assemblies may be sufficient).

Projecting from one end of the frame 12 is a tongue attachment bracket46, which includes a pair of spaced apart, rectangular shaped plates 48and 50 fixed to the underside of the cross-plate 28. The plates 48 and50 present aligned openings (not visible in the drawing figures)configured to receive a retaining pin 52 therein.

In this respect the illustrated tongue 14 includes a square-shaped tube54 having an opening (also not visible in the drawing figures) adjacentone end thereof, with the opening similarly being configured to receivethe retaining pin 52 therein. The tube 54 is consequently swingableabout a substantially horizontal axis defined by the pin 52. Acylindrical rod 56 is preferably fixed to the distal end of the tube 54for presenting a handle that may be grasped by the user duringmanipulation of the cart 10.

A second tongue attachment bracket 58 is provided on the side of theframe 12. The side bracket 58 similarly includes a pair of plates 60 and62, although the plates 60,62 are fixed to the outer side of the beam26. The plates 60 and 62 present aligned openings 64 and 66 configuredto receive the retaining pin 52. Accordingly, the tongue 14 may beconnected to the frame 12 by either bracket 46 or 58, with movement ofthe tongue 14 from one bracket to another simply requiring removal ofthe pin 52, alignment of the openings in the tongue and other bracket,and insertion of the pin 52 into the aligned openings. It is noted thatthe tongue 14 projects in relatively transverse directions when attachedto the brackets 46 and 58.

The frame 12 and tongue 14 are preferably formed of metal, althoughother suitable materials (e.g., high strength plastic) may be used. Inaddition, the means by which components of the frame 12 and tongue 14are fixed to one another may be varied as desired, although suitablewelding techniques are preferred.

The parallelogram linkage 20 includes two equal-length bars 68 and 70(e.g., see FIG. 3), each of which comprises a respective pair oflaterally spaced apart links 68 a,68 b and 70 a,70 b. The links 68 a and70 a are pivotally connected to the beam 24 by respective fasteners 72and 74 (e.g., standard nut and bolt assemblies), and the links 68 b and70 b are similarly connected to the beam 26 by fasteners 76 and 78(e.g., see FIG. 2). The pivot connections for the links 68 a,68 b or 70a,70 b of each bar 68 or 70 are aligned. Each of the links 68 a,68 b,70a,70 b is preferably formed of a square-shaped metal tube, although anysuitable material may be used. It is noted that the links 68 a and 68 bare interconnected by a brace 80, with the brace being preferably weldedbetween the links when these components are formed of metal. Althoughnot shown, a similar brace may be fixed between the links 70 a and 70 bif desired.

A pair of U-shaped connectors 82 and 84 extend between and serve toconnect the upper ends of the links 68 a,70 a and 68 b,70 b,respectively. If desired the connectors 82 and 84 may be formed of thesame material as the beams 24 and 26. Similar to the opposite ends ofthe links, fasteners 86,88,90,92 (see FIGS. 1 and 3) are provided topivotally attach the links to corresponding ones of the connectors 82and 84. In addition, the upper pivot connections for the links 68 a,68 bor 70 a,70 b of each bar 68 or 70 are aligned. Because of the parallelarrangement of the linkage 20, the upper pivot connections for the links68 a and 70 a are spaced apart the same distance as the lower pivotconnections, and the same may be said of the pivot connections for thelinks 68 b and 70 b. The plate holders 16,18 are fixed to one end of theconnectors 82,84, whereby the linkage 20 supports the holders 16,18 onthe frame 12 for relative up and down movement.

The linkage 20 is attached is coupled to the frame 12 closer to one endof the beams 24,26 than the other and is generally disposed over theframe 12. Thus, movement of the linkage 20 is generally limited to thearea above the frame 12, although the linkage 20 may be folded down toan orientation relatively close to the ground as a result of the lowprofile of the frame 12 (e.g., see FIG. 4). However, it will beappreciated that the principals of the present invention are equallyapplicable to various other frame and linkage arrangements. For example,the device may include a relatively taller frame with the parallelogramlinkage projecting from one of the ends or sides of the frame to supportthe plate holder(s) thereon. In any case, it is preferred that thedevice be configured so that the plate holder(s) be positionablerelatively close to the ground.

Movement of the linkage 20, and thereby adjustment of the height of theplate holders 16 and 18, is controlled by the actuator 22. In theillustrated embodiment, the actuator 22 comprises a hand-operatedhydraulic piston and cylinder assembly including a cylinder 94 housingthe piston (not shown) and a rod 96 telescopically received within thecylinder 94 and attached to the piston. This type of assembly is oftenreferred to as a “bottle jack”, although any suitable actuator (e.g., aratchet-type lift) may be used. In the usual manner, the jack 22includes a pedestal 98, from which the cylinder 94 projects, and a crankmechanism 100 that controls extension of the rod 96 relative to thecylinder 94. The mechanism 100 also includes a removable arm 102 and arelease screw (not shown) that permits retraction of the rod 96 whenactivated. As is also customary, a screw 103 is threadably connected tothe distal end of the rod 96.

The jack 22 is pivotally coupled to the frame 12 by a pivot assembly104, as perhaps best shown in FIGS. 1 and 3. The assembly 104 includes acylindrical rod 106 fixed between the beams 24 and 26, a sleeve 108slidably received on the rod 106, and a mounting plate 110 bolted to theunderside of the pedestal 98 and secured to the sleeve 108 in atangential relationship. The opposite end of the jack 22 is attached toan arm 112 that serves to couple the former with the linkage 20. Theillustrated arm 112 includes a pair of side plates 114 and 116 pivotallyattached to respective ones of the links 68 a and 68 b by fasteners 118and 120 (e.g., see FIGS. 1 and 2). A square-shaped metal tube 122 ispreferably welded between the side plates 114 and 116, with the tube 122presenting an opening 124 (see FIG. 3) configured to receive the screw103 therein. An opening 125 (see FIGS. 1 and 2) is also defined in thetube 122 for receiving the crank arm 102 therein during periods ofnon-use (e.g., see FIG. 4).

Extension of the rod 96 relative to the cylinder 94 causes the linkage20 to unfold and thereby raise the plate holders 16 and 18. It is notedthat FIG. 3 illustrates the rod 96 in the fully extended condition andthe holders 16 and 18 in the fully raised position. On the other hand,when the rod 96 is retracted, the linkage 20 folds and the plate holders16 and 18 are consequently lowered. The fully lowered positions of theholders 16 and 18 is illustrated in FIG. 4. The parallelogram linkage 20insures that the orientation of the plate holders 16 and 18 remainssubstantially constant as it is raised and lowered.

Turning now to the preferred construction of the holders 16 and 18, theplate holder 16 comprises an L-shaped element presenting a generallyupright wall 126 and a transverse wall ,130. It is noted that the holder16 is disposed at a slight angle relative to horizontal so that the wall130 slopes downwardly toward the upright wall 126 (see FIGS. 3 and 4).This is preferably accomplished by tapering the upper edge of theconnectors 82 and 84 adjacent the corresponding end (e.g., by grinding,cutting, etc.) and then fixing the wall 128 to the tapered end of theconnectors 82 and 84. The plate holder 16 is preferably formed of thesame material as the connectors 82 and 84. Particularly, the preferredholder 16 is formed of standard angle iron and is welded to theconnectors 82 and 84.

The wall 128 defines an upwardly facing support surface havingsufficient length to support the replaceable plates thereon. As will bedescribed further below, the upright wall 126 serves to support thereplaceable plates in an upright orientation when they are supported onthe wall 128. A nut and bolt assembly 130 is attached to the wall 128 ata location spaced from the upright wall 126 to define a projection thatassists with retaining the replaceable plates in the uprightorientation. Those ordinarily skilled in the art will appreciate,however, that the projection may be variously constructed (e.g., theprojection may be formed by a block-welded to the upper surface of thewall 128). It is also noted that the angled orientation of the support16 further assists with retaining the plates in the upright orientation.

The plate holder 18 similarly comprises a pair of generally L-shapedelements projecting forwardly from the connectors 82 and 84,respectively, and cooperatively presenting a generally upright wall 132and a bottom support wall 134. It is noted, however, that the walls 132and 134 of the holder 18 are not transverse relative to one another.Instead, the upright wall 132 is disposed at an obtuse angle (e.g.,120°) relative to the generally horizontal wall 134. One of thereplaceable plates may consequently be placed on the support wall 134and supported in a generally upright orientation by the wall 132. Theends of the connectors 82 and 84 serve to retain the plates supported onthe wall 134 in the generally upright orientation. This is facilitatedby the angle of the wall 132 relative to the wall 134.

In view of the foregoing, it will be appreciated that the cart 10 may beused to facilitate replacement of virtually any type of plate used onthe blade of a plow or grader. In addition, the cart 10 can be usedduring replacement of plates on various types of blades. For example, asnow plow will often include a front blade supported ahead of thevehicle, a side-mounted wing blade supported alongside the vehicle,and/or an underbody blade mounted under the vehicle between the frontand rear wheels. For purposes of illustration, FIGS. 1-3 depictinstallation of a cutting edge 136 and a wear plate 138 to a front blade140, while FIG. 5 illustrates installation of the cutting edge 136 to anunderbody blade 142.

Turning first to FIGS. 1-3, the cutting edge 136 is preferably placed inan upright orientation on the wall 128 between the projection 130 andthe upright wall 126. The cutting edge 136 may be placed on the supportwall 128 when the linkage 20 is folded so that the holder 16 is in itslowermost position, thereby reducing the amount the edge 136 must belifted by the worker. In fact, only one end of the edge 136 need belifted onto the support 16 and then the edge 136 may be slid lengthwisetoward the propped-up end until the center of gravity of the edge 136 issecurely positioned over the holder 16. The actuator 22 is then operatedby cranking the arm 102 so that the rod 86 extends to raise the holder16. Once the edge 136 is in general vertical alignment with the lowerboundary of the blade 140, the cart 10 is preferably moved intoproximity with the blade 140 until the edge 136 contacts the front faceof the blade 140. Such movement of the cart 10 is, of course,facilitated by the tongue 14. The plate holder 16 is further raised andlowered and the cart 10 may be further moved so that the attachmentholes 144 defined in the edge 136 are brought into alignment with thecorresponding attachment holes 146 defined in the blade 140. Bolts 148are preferably then inserted through the aligned attachment holes 144and 146. If desired, the bolts 148 may be inserted before or as theholes 144 and 146 are aligned to facilitate such alignment. In addition,pins (not shown) may be inserted into one or more of the holes 144 or146 defined in the edge 136 or blade 140 to facilitate such alignment.As perhaps best shown in FIG. 3, the holder 16 is preferably arranged sothat the orientation of the plate supported on the holder 16 (the wearplate 138 in the case of FIG. 3) generally corresponds to that of thefront blade 140, which further facilitates alignment of the attachmentholes 144 and 146. It is also noted that the upright wall 126 isdimensioned so that it does not get caught between the edge 135 andblade 140 during installation.

The cutting edge 136 is divided into sections that are relativelyshorter than the blade 140, such that each section must be individuallyinstalled. The cutting edge 136 and wear plate 138 are traditionally thesame length (considering the aggregate length of the cutting edgesections), however, the wear plate 138 is traditionally not sectionedbut rather comprises a single piece extending the entire length of theplow 140. Nonetheless, the wear plate 138 is installed in generally thesame manner as the cutting edge 136. Thus, it shall be sufficient toexplain that the wear plate 138 is positioned on the support 16 so thatthe center of gravity of the plate 138 is disposed over the wall 128.The height of the holder 16 is adjusted and the cart 10 is moved asnecessary to align the attachment holes in the wear plate 138 with thecorresponding attachment holes 146 defined in the blade 140. It will beappreciated that the bolts 148 projecting forwardly from the cuttingedge 136 will facilitate such alignment. As shown in FIG. 3, the uprightwall 126 will be disposed between the cutting edge 136 and wear plate138 once the attachment holes are aligned. This will consequentlyrequire the holder 16 to be lowered or the cart 10 to be moved laterallybeyond one of the ends of the blade 140 so as to remove the wall 126from the space between the plates 136 and 138 and thereby permit thewear plate 138 to be placed against the cutting edge 136. If the cart 10is to be moved laterally, the tongue 14 may be installed on the sideattachment bracket 58 to facilitate such movement.

The plate holder 18 operates in generally the same manner as the plateholder 16. However, the plate holder 18 is designed to support thecutting edge 136. and wear plate 138 at a slightly smaller anglerelative to horizontal, as perhaps best shown in FIG. 4. In particular,the cutting edge 136 is supported by the holder 18 at an angle that moreclosely corresponds to the angle of the underbody blade 142. Thoseordinarily skilled in the art will appreciate that there istraditionally little clearance (e.g., five to seven inches) below theunderbody blade 142. The plate holder 18 is particularly effectiveduring replacement of plates on the underbody blade 142 because of itsrelatively lower location on the cart 10. It will also be appreciatedthat plate holder 18 is typically disposed at or near its lowermostposition during installation of the plates on the underbody blade 142,and consequently, there will be little, if any, adjustment of the heightof the plate holder 18 as the attachment holes are aligned. As shown inFIG. 4, the upright wall 132 of the plate holder 18 is disposed behindthe cutting edge 136. Because the plate holder 18 is at or near itslowermost position, the cart 10 will need to be moved laterally beyondone of the ends of the blade 142.

An alternative embodiment of the present invention is shown in FIGS. 5and 6, wherein an extension boom 200 is provided on the cart 201. Theextension boom 200 is designed to hold both the cutting edge 136 and thewear plate 138. Moreover, as perhaps best shown in FIG. 5, the extensionboom 200 is of sufficient length to simultaneously support all of thecutting edge sections. In this respect, installation of the entirecutting edge 136 and the wear plate 138 may be accomplished at one time.

The extension boom 200 preferably comprises a U-shaped channelpresenting a bottom support wall 202 and a pair of spaced apart uprightwalls 204 and 206. The cart 201 is generally similar to that shown inFIGS. 1-4, with the extension boom 200 preferably being attached to theplate holder 208 so as to be carried on the cart frame (not shown) bythe parallelogram linkage 210. It is particularly noted that suchattachment is accomplished by a plurality of nut and bolt assemblies 212that cooperatively present a projection on the support wall 202 spacedfrom the upright wall 206. A pair of clamping mechanisms 214 (only oneof the clamping mechanisms being shown in the drawing figures) areattached to the upright wall 204. As shown in FIG. 5, each of themechanisms includes a shiftable clamping element 216 projecting throughan open slot 218 defined in the wall 204, for purposes which willsubsequently be described. One suitable clamping mechanism is availableas Part No. 210 from Dover Resources Co. of Troy, Mich. However, it isentirely within the ambit of the present invention to utilize variousother clamping mechanisms (e.g., a traditional C-clamp would suffice).

The extension boom 200 is used in virtually the same manner as the plateholders 16 and 18, although the boom 200 does have a few beneficialexceptions. The sections of the cutting edge 136 are preferably firstplaced end-to-end on the support wall 202, with the nut and boltassemblies 212 serving to maintain the edge 136 in an uprightorientation against the wall 206. It is noted that the illustrated boom200 is not quite as long as the edge 136, however, the boom 200 is ofsufficient length to ensure that the center of gravity for each of theoutermost sections may be securely disposed over the support wall 202.The unitary wear plate 138 is then placed on the support wall 202between the cutting edge 136 and the nut and bolt assemblies 212. Theattachment holes defined in the plates 136 and 138 are subsequentlyaligned, which should occur naturally when the plates are superimposed.If desired, pins 220 may be inserted into the aligned attachment holes,with at least one pin preferably being associated with each section ofthe cutting edge 136. The clamping mechanisms 214 are then operated toclamp the plates 136 and 138 to one another and against the upright wall206. The alignment pins 220 may be removed at this time, although theyare preferably left in the attachment holes to facilitate attachment tothe blade 140. The height of the boom 200 may then be adjusted and thecart 201 may be moved until the pins 220 are received in thecorresponding attachment holes defined in the blade 140. Bolts (notshown) can subsequently be inserted into the open attachment holes (theholes not having a pin received therein), and the pins 220 may then beremoved so that the remaining bolts can be installed. Thereafter, theplates 136 and 138 are unclamped and the cart 201 can be moved away fromthe blade 140.

The preferred forms of the invention described above are to be used asillustrations only, and should not be utilized in a limiting sense ininterpreting the scope of the present invention. Obvious modificationsto the exemplary embodiments, as hereinabove set forth, could be readilymade by those skilled in the art without departing from the spirit ofthe present invention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as pertains to any apparatus not materially departingfrom but outside the literal scope of the invention as set forth in thefollowing claims.

What is claimed is:
 1. A method of installing replaceable, elongatedplates on the blade of a plow or grader, said method comprising thesteps of: (a) supporting at least one plate on a mobile cart, furtherincluding the step of placing the at least one plate on an angularlyheight adjustable plate holder of the cart; and (b) aligning attachmentholes defined in the at least one plate with corresponding attachmentholes in the blade, further including the step of angularly adjustingthe height of the holder incrementally and thereby the height of the atleast one plate incrementally.
 2. An installation method as claimed inclaim 1, step (b) including the step of attaching the at least one plateto the blade.
 3. An installation method as claimed in claim 2, saidattaching step including the step of inserting a bolt through at leastone of the aligned attachment holes defined in the plate and blade. 4.An installation method as claimed in claim 1, step (a) including thestep of substantially superimposing one plate over another plate, suchthat two superimposed plates are supported on the cart, step (a) furtherincluding the step of aligning corresponding attachment holes defined inthe plates.
 5. An installation method as claimed in claim 4, step (a)including the step of clamping the superimposed plates to one another.6. An installation method as claimed in claim 4, step (a) including thestep of inserting a removable alignment element in at least one of thealigned attachment holes of the plates.
 7. An installation method asclaimed in claim 6, step (b) including the step of inserting thealignment element into a corresponding one of the attachment holesdefined in the blade; and (c) attaching the superimposed plates to theblade before the alignment element is removed.
 8. An installation methodas claimed in claim 1, step (b) including the step of moving the cartinto proximity with the blade.
 9. An installation method as claimed inclaim 1, wherein the angular orientation of said plate holder remainssubstantially constant as the holder is raised or lowered in height.